Twist-lock snap-in contact



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United v States Patent 3,031,639 TWIST-LOCK SNAP-IN CONTACT Stanley J. Maiewski, Chicago, Ill, assignor to United- Carr Fastener Corporation, Boston, Mass, 2 corporation of Delaware Filed Mar. 21, 1960, Ser. No. 16,408 Claims. (Cl. 339217) This invention relates to a connector and contact structure, and more particularly to a removable contact structure that in a general sense may be considered to be a snap-in type contact. The invention is especially useful with closed-entry contact structures and the connector parts therefor.

The usual connector comprises two complementary parts formed of insulating material, and each such part is provided with a plurality of cavities oriented in longitudinally and transversely extending rows, and each cavity is adapted to receive a contact structure therein. The contact structures in one of the connector parts constitute the female or socket components, while those in the other connector part constitute the male or prong components which are adapted to be respectively inserted into the socket components so as to establish an electric connection therewith.

The number of contact structures provided by a connector varies in accordance with the size and intended use therefor, but in any event a substantial number of contact structures are usually included. Thus, an ass mbly difiiculty isencountered in that each contact structure must be electrically and mechanically connected to one of a plurality of conductors; and because of space limitations, it is diflicult to solder or otherwise connect such conductors to the respective contact structures after the structures are mounted Within the cavities therefor in the connector parts. Consequently, the most desirable arrangement is to respectively connect the conductors of the contact structures prior to mounting the latter in the connector part cavities, and such an arrangement usually necessitates the provision of a snap-in type contact structure (that is, one which is inserted into the cavity therefor by moving the contact structure along the longitudinal axis of the cavity, and which automatically seats and locks itself within the cavity when the structure is inserted to its full extent).

An object of the present invention is to provide an improved contact structure and connector composition in which a positive locking arrangement is provided which constrains the contact structure against longitudinal dis placements in either direction irrespective of the magnitude of the force applied theretoin contrast to the conventional snap-in contact wherein longitudinal displacements are yieldingly resisted by spring locks.

Another object is in the provision of a removable contact structure and connector composition wherein there is substantially no deterioration of the quality and effectiveness of the lock constraining the contact structure against longitudinal displacements irrespective of the number of times the contact structure is removed from and reinserted into the connector cavity therefor-in contrast to the conventional snap-in contact wherein the spring lock rapidly deteriorates and becomes ineffective after several insertions and removals thereof. Still another object is that of providing a composition of the type described, in which the longitudinal movement of the contact structure into and out of the cavity therefor in no way deforms or otherwise stresses the elements that constrain the structure against longitudinal displacements when the contact structure is locked within its cavity.

A further object is to provide a closed-entry contact structure (both the male and female component) and connector composition, in which the contact structure is inserted longitudinally into its cavity to a predetermined position in which further movement in the same direction is positively constrained, and in which the contact structure is then rotated slightly about its axis to establish the positive interlock that constrains the contact structure against longitudinal movement in the opposite direction. Still a further object is that of providing a closed-entry contact structure of the character described, in which means are provided to maintain the contact structure in the rotated position thereof by yieldingly resisting rotation of the structure from such position.

Yet a further object is in the provision of a contact structure as described that is structurally simple, relatively inexpensive, direct and positive in its function, and that does not necessitate the use of expensive and complicated tools and manipulations in inserting the contact structure into its cavity or in removing the structure therefrom. Additional objects and advantages of the invention will become apparent as the specification proceeds.

An embodiment of the invention is illustrated in the accompanying drawing, in which- FIGURE 1 is a broken longtudinal sectional view of a closed-entry contact structure including both the male and female components thereof, as respectively mounted in the connector parts therefor and with the parts and contact components in cooperative association; FIGURE 2 is an enlarged, perspective view of the female component of the closed-entry contact composition illustrated in ,FIGURE 1; FIGURE 3 is a perspective view of the locking band used with the contact structure; FIGURE 4 is an enlarged, transverse sectional view taken along the line 44 of FIGURE 1; FIGURE 5 is an enlarged,

FIGURE 1; and FIGURE 6 is an enlarged, transverse sectional view similar to that of FIGURE 5, but showing the contact structure rotated slightly from the position thereof illustrated in FIGURE 5.

An exemplification of the invention is illustrated in FIGURE 1 in the form of a closed-entry contact structure and connector composition, and it comprises connector parts 10 and 11 having contact structures 12 and 13 respectively mounted in cavities 14 and 15 provided by the connector parts '10 and 11. The connector parts 10 and 11 are substantially similar, as are'the cavities 14 and 15 respectively provided thereby; and the connector parts are formed of an insulating material and, for exmple, may be Bakelite castings. The contact structure 12 is a male component having a prong or pin 16 inserted into a passage or socket 17 provided by the female closed-entry contact component 13. The interconnection of the prongs 16 and sockets 17 is exemplary only and may take varied structural forms, all of which are designed to establish a good electrical connection between the prong and socket and consequently between the male and female components 12 and 13. It will be understood thatthe connector parts 10 and 11 will respectively provide a plurality of cavities each having a contact structure therein, and such cavities and contacts are ordinarily arranged in multiple transversely and longitudinally extending rows oriented so that the various male contacts of the connector part 10 respectively enter the correlated female components provided by the female connector part 11.

The contact structures 12 and 13 are identical except for the prong and socket respectively provided thereby, but such difference has no bearing on the present invention and therefore as a convenience the numerals hereinafter employed to designate the various elements of these contact structures will be applied interchangeably to each. Referring then to FIGURE 2, the contact structure there illustrated is elongated and has a body or barrel 18 of a generally cylindrical configuration, and at its outer end the barrel d3 has an enlargement 19 provided with a passage (not shown) therein that may extend into the reduced portion of the barrel is, and which is adapted to receive the leads of a conductor therein which are electrically and mechanically connected to the contact structure by flowing molten solder into the passage. Other arrangements may be used for making such connection between the conductor and contact structure.

Intermediate its ends and at substantially the center portion thereof, the contact structure is equipped with an outwardly/extending annular flange 20 that defines a stop, and spaced forwardly and longitudinally from the flange 2% are a pair of oppositely oriented abutment members 21 and 22 that extend laterally outwardly from the barrel and have flattened or generally planar side Walls that give the abutment members (when considered together) a generally rectangular configuration. The composite transverse dimension of the members 21 and 22 is substantially the same as the diameter of the flange 20. Intermediate the flange 2t and stop members 21-42 is a portion or section 23 of reduced diameter having flattened or planar Wall portions respectively corresponding to those of the stop members. Considering the stop members and intermediate section as an integer, they have a generally T-shaped configuration. I

Adapted to be mounted about the intermediate portion 23 is a locking structure in the form of a compressible band 24 made of stainless steel or other resilient or spring-like material, whereby the band tends to assume the expanded or unstressed state thereof shown in FIG- URE 3. The band is bent about the portion 23-, and has flattened or generally planar side walls 25 and 26 respectively disposed in contiguous relation with the planar side walls-f the portion 23; and as a result, relative rotation between the contact structure and band is prevented. The longitudinal dimension of the band 24 is such that it extends substantially from the flange 20* to the abutment members 21 and 22, and therefore longitudinal displacements of the band relative to the contact structure are prevented by those elements.

The band 24 is provided with a pair of oppositely oriented protuberances in the form of longitudinally extending ribs 27 and 28, and the wall 26 has a substantial gap between the adjacent longitudinal edges thereof when the band is in its non-stressed state so as to enable the band to be compressed with the ribs 27 and 28 displaced generally toward each other. In order to prevent substantial twisting of the band during compression thereof, the wall 26 may have a tongued portion 29 and slot portion 30 adapted to receive the tongue therein.

As indicated hereinbefore, the cavities 14 and are substantially identical, and therefore as a convenience the same numerals will be hereinafter employed to designate the pertinent elements of the cavities and associated connector part elements. Each cavity is provided with a pair of transversely spaced and facing abutment elements 61 and 32 that extend into the cavity at substantially the center portion thereof. The inner edges of the abutment elements are in spaced apart, parallel relation and respectively define chords of the circular cross section of the cylindrical cavity, as shown best in FIGURES 4 through .6. Thus, the abutment elements define a passage 33 therebetween, and such passage has a generally rectangular configuration conforming generally to such configuration of the abutment members 21 and 22. The abutment elements 31 and 32 are respectively provided with recesses along the facing inner edges thereof defined by longitudinally extending channels 34 and 35.

In assembling the contact structures with the connector parts, each contact structure is first soldered or otherwise secured to the conductor therefor, and the contact is then moved longitudinally into its cavity--from left to right in the case of the contact 12 and from right to left in the case of the contact 13, as each is shown in FIGURE 1. During this longitudinal insertion of each contact Structure, the maximum transverse dimension of the abutment members 21 and 22 is aligned with the mam'mum transverse dimension of the passage 33 so that the abutment members can be moved bodily through the passage. Considering such alignment further, the contact structure and particularly the abutment members 21 and 22 thereof will be rotated from the position thereof illustrated in FIGURES 4 and 5; or considering FIGURE 6, the rotation will be continued in a clockwise direction until the maximum transverse dimension of the abutment members lies along the horizontal x-axis of the usual rectangular coordinant axes. With such alignment, the contact structure can be inserted completely into the cavity therefor, and such longitudinal insertion continues until the flange or stop 2 engages the abutment elements 31 and 32 which then effects a constraint preventing further movement of the contact structure in one longitudinal direction.

The connector structure is now positioned so that the abutment members 21 and 22 are disposed along a plane defined by the opposite side or face of the abutment elements 31 and 32, thereby permitting rotation of the contact structure Within the cavity. When the contact structure is so rotated through an arc of substantially 90, the abutment members 21 and 22 will be respectively disposed along the faces of and in cooperative relation with the abutment elements 31 and 32, whereupon the contactstructure is constrained against movement within the cavity in the opposite longitudinal direction. Thus, the contact structure is now positively locked within its cavity and cannot be displaced longitudinally in either direction, irrespective of the magnitude of a longitudinally directed force applied thereto, disregarding .a force having a magnitude sufficient to destroy or break the connector part .and/ or the contact structure.

As the contact structure is rotated, the ribs 27 and 28 of the compressible band 24 will be brought into engagement with the abutment elements 31 and 3 2, and as a consequence of continued rotation the band will be compressed with the ribs 27 and 28 being displaced toward each other and into the position shown in FIGURE 6. As the contact structure is rotated even farther in the same direction, the ribs 27 and 28 will come into respective alignment with the channels 34 and 35 and will snap thereinto because of the inherent resilience or spring-like characteristics of the band 24. This latter position of the ribs is illustrated in FIGURE 5. The band 24 is now efiective to resist rotation of the contact structure from the locked position thereof (which may be considered the first position in which the contact members 21 and 22 are disposed in cooperative relation with the abutment elementsfil and 32) into a second position in which the abutment members 21 and 22 are disengaged from the abutment elements 31 and 32, whereupon the contact structure can be displaced longitudinally Within the cavity.

It will be noted that the channels 34 and 35 have a generally arcuate configuration, as do the ribs 27 and 28, and therefore a torque of sufficient magnitude applied to the contact structure when the ribs are in the channels will cause the ribs to be cammed inwardly toward each other, thereby compressing the band and permitting the contact structure to rotate into the aforementioned second position. In the specific embodiment shown, the contact structure can be rotated selectively in either direction through a full 360, and at alternate 90 intervals the contact structure will be in its first locked position and the aforesaid second position. It will be apparent that a simple tool may be employed to effect rotational movements of the contact structure; and since the biasing force of the band or locking structure 24 is employed only for purposes of resisting rotation, the contact structure may be repeatedly removed from and inserted into the cavity without. destroying the positive character of the constraint against longitudinal displacements applied thereto.

While in the foregoing specification an embodiment of the invention is set forth in considerable detail for purposes of making a complete disclosure thereof, it will be apparent that numerous changes may be made in such details without departing from the spirit and principles of the invention.

I claim:

1. In combination, a connector part having a longitudinally extending cavity therein and providing an abutment element extending into said cavity, a contact structure mounted within said cavity and being constrained therein against longitudinal movement in one direction relative thereto, said contact structure being provided with an abutment member extending laterally outwardly therefrom and being rotatable Within said cavity between a first position in which said abutment member is disposed in cooperative engagement with said abutment element to constrain said contact structure against longitudinal movement in the opposite direction and a second position in which said abutment member is disengaged from said abutment element to enable said contact structure to be moved in such opposite longitudinal direction for withdrawing the same from said cavity, and a compressible locking structure carried by said contact structure and being compressively engaged by said connector part in the first position of said contact structure to resist rotational movement thereof into said second position and being in a substantially non-stressed state in the second position of said contact structure so as to uninhibit longitudinal movements thereof.

2. The combination of claim 1 in which said locking structure is disposed within said cavity and is equipped wth a protuberance, and in which said connector part is provided with a recess releasably receiving said protuberance therein in the aforesaid first position of said contact structure.

3. The combination of claim 1 in which said locking structure comprises a band substantially encircling a por tion of said contact structure, and in which cooperative means are respectively provided by said band and contact structure to prevent substantial rotational movements of one relative to the other.

dinally extending cavity therein and providing a pair of facing abutment elements extending into said cavity and defining a passage therebetween, a contact structure mounted within said cavity and being constrained therein against longitudinal movement in one direction relative thereto, said contact structure being provided with a pair of oppositely oriented abutment members extending laterally outwardly therefrom and being rotatable within said cavity between a first position in which said abutment members are respectively disposed in cooperative engagement with said abutment elements to constrain said contact structure against longitudinal movement in the opposite direction and a second position in which said abutment members are disengaged from the respectively associated abutment elements, said abutment members in such second position of said contact structure being longitudinally movable through said passage and between said abutment elements to enable said contact structure to be selectively inserted into said cavity and to be withdrawn therefrom, and a compressible locking band carried by said contact structure adjacent said abutment members and about the portion of said contact structure disposed within said passage in such first position and being compressively engaged by at least one of said abutment elements in said second position of said contact structure to resist rotational movement thereof into said second position and being in a substantially non-stressed state in such second position of said contact structure so as to uninhibit longitudinal movements thereof.

5. The combination of claim 4 in which said band is equipped with a protuberance, and in which the aforesaid one abutment element is provided with a recess releasably receiving said protuberance therein in such second position of said contact structure.

References Cited in the file of this patent UNITED STATES PATENTS 2,272,379 Loukota et al Feb. 10, 1942 2,389,454 Picard NOV. 20, 1945 2,411,861 Antony et a1 Dec. 3, 1946 2,419,018 Gudie Apr. 15, 1947 2,477,849 Adams Aug. 2, 1949 

